Chemical peeling with salicylic acid in polyethylene glycol vehicle suppresses skin tumour development in hairless mice

SummaryBackground Chemical peeling with salicylic acid in polyethylene glycol (PEG) vehicle is used clinically to improve the cosmetic appearance of skin that has been damaged by exposure to the sun. It is well known that cancers of the skin such as basal cell carcinoma and squamous cell carcinoma may be induced by the sun. However, the carcinogenic potential of chemical peeling agents has not been studied. Objectives To evaluate the effects of chemical peeling with 30% salicylic acid in PEG on skin tumour formation in treated vs. control mice. Methods To serve as a model of sun-damaged skin, hairless SKH/hr1 mice were irradiated with ultraviolet (UV) B for 14 weeks, with or without treatment every 2 weeks with 30% salicylic acid in PEG for a total of 18 weeks. Results Not only was the total number of tumours greatly reduced in the treated vs. the control mice, but skin tumour development was also slower in the treated vs. the control mice. At the final treatment, the fractions of T and B lymphocytes and natural killer cells from spleens of both groups of mice were comparable, and interferon-γ production did not differ. Conclusions Our findings suggest that chemical peeling with salicylic acid in PEG may help to prevent as well as to reduce the number of UVB-induced skin tumours.